Title

Author

Abstract

The overwhelming changes in the field of communication brought about need for high data rates, which led to the development of a system known as Long Term Evolution (LTE). LTE made good use of Orthogonal Frequency Division Multiplexing Access (OFDMA) in its downlink and Single Carrier Frequency Division Multiplexing Access (SCFDMA) in its uplink transmission because of their robust performance. These multiple access techniques are the major focus of study in this thesis, with their implementation in the LTE system.

GNU Radio is a software Defined Radio (SDR) platform. It comprises of C++ signal processing libraries. For user simplicity, it has graphical user interface (GUI) known as GNU Radio Companion (GRC), to build a signal processing flow graph. GRC translates any specific task flow graph to a python program which calls inbuiltC++ signal processing blocks. By leveraging this feature and existing modules in GRC, OFDMA and SCFDMA is implemented. In this study we made use of existing OFDMA flow graph of GNU Radio to study the behavior of downlink and general performing SCFDMA system was implemented with some modifications of the existing GNU Radio blocks.

With the GNU Radio implementation, we tested the working mechanism of both the systems. OFDMA is used in downlink for achieving high spectral efficiency and SCFDMA was introduced in uplink due to its low PAPR feature. These multiple access schemes have to meet the requirement of high throughput with low BER and PAPR, low delays and low complexity. In this thesis we are focused on evaluating these multiple access techniques in terms of BER and PAPR with modulation techniques like QPSK, 16-QAM and 64-QAM. Performance analysis part is performed in MATLAB.